[@古散][¥20]Java如何将图片转化为二进制格式的字符而不是二进制流（如附件图片的格式）

import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class TestImageBinary {

static BASE64Encoder encoder = new sun.misc.BASE64Encoder();   
static BASE64Decoder decoder = new sun.misc.BASE64Decoder();   
   
public static void main(String[] args) {   
    System.out.println(getImageBinary());   
       
    base64StringToImage(getImageBinary());   
}   
   
static String getImageBinary(){   
    File f = new File("f://123456.jpg");    //这里gif动态图不可以，虽然在后面也能输出gif格式，但是却不是动图
    BufferedImage bi;   
    try {   
        bi = ImageIO.read(f);   
        ByteArrayOutputStream baos = new ByteArrayOutputStream();   
        ImageIO.write(bi, "jpg", baos);   
        byte[] bytes = baos.toByteArray();   
           
        return encoder.encodeBuffer(bytes).trim();   
    } catch (IOException e) {   
        e.printStackTrace();   
    }   
    return null;   
}   
   
static void base64StringToImage(String base64String){   
    try {   
        byte[] bytes1 = decoder.decodeBuffer(base64String);   
           
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes1);   
        BufferedImage bi1 =ImageIO.read(bais);   
        File w2 = new File("f://meinv.bmp");//可以是jpg,png格式   
        ImageIO.write(bi1, "jpg", w2);//不管输出什么格式图片，此处不需改动   
    } catch (IOException e) {   
        e.printStackTrace();   
    }   
}   

}

这一幕是干啥的